Sometimes I don’t have the time to actually take my boat out for two or three weeks at a time, but I do have time to run her Cummins diesels now and again. How often, how long, and at what rpm should I do this?
Ask Professor Diesel
I left my marina with my seacocks closed. How do I know if I’ve damaged a head gasket or something else?
Should we do end-of-season oil changes or can we stretch the old oil into the next season?
I plan on being away from my boat for two to three months and during that time, I plan on having someone periodically run my diesels dockside...
Question: I have a 1989 38-foot Bayliner with twin 175-hp Hino diesels that have been retrofitted with turbochargers, thus raising each engine to 210 horsepower. As I go from cruise to wide-open throttle (approximately 23 mph at 2800 rpm), turbo exhaust temperatures increase from 700F to 950F on the port engine and 850F on the starboard. When
Question: The boys at the Ko Olina harbor are having a heated discussion concerning motor oil. Since Costco hit town, we’ve all been able to buy Chevron 15W-40 Delo 400 heavy-duty motor oil at ridiculously low prices. But what about the older engines we’ve been using straight 40W Delo 400 and other single-viscosity products in for years? Can we
Question: I own a 1996 43-foot Hatteras with twin six-cylinder Detroit Diesel engines. I change the oil approximately every 100 hours of operation. At this point, I have 1,200 hours on each diesel and so far have only used non-synthetic oil. Is a synthetic or a blend of synthetic and regular oil contraindicated for this aged engine for any
Question: I have a 29 Phoenix with twin, 1984-vintage, 170-hp Yanmar diesels with 1,000 hours on them. While the boat seems to run fine, I have one issue. During operation, the temperature of each engine rises normally at first but then keeps on going, not to the point of setting off alarms, but close. Pegging the engines (i.e., throttling them
Question: When I took your one-day Introductory Diesel Maintenance Course several years ago, I forgot to ask one question: What is the best way to lay up a fuel tank for seasonal storage? For years now, I’ve been topping off my tanks when fall lay-up comes around in order to reduce the air space above the fuel and thus minimize algae growth. Just
Question: I just did my first oil analysis on my Cummins 6BTA diesel, and the results seem somewhat disconcerting. According to the report, there was aluminum in the oil at 28 ppm (parts per million) and iron at 20 ppm. The oil that was tested had approximately 43 engine hours on it. And since I bought my boat some nine years ago, I have
Question: I have a 1989 Sea Ray with 375-hp Caterpillar 3208 diesels. Last year I overheated one of them and blew a head gasket. Overheating had been a problem for some time prior, incidentally. Anyway, I determined shortly thereafter that the gasket had blown into the cylinder although no cooling fluid had escaped. So I hired a diesel shop to
Question: I have a 4-kW Marine Onan genset with 600 hours on it. If I let it run for a lengthy period it produces so much black smoke that a residue discolors the hull around the exhaust port. A year ago, I cleaned the heat exchanger and installed a new raw-water pump. There are no overheating issues. Do I have an injector or rack problem?—Charlie Carpenter, Morristown, New
Question: I have a pair of Detroit Diesel 6-71 TIBs in my 1990 Ocean 48 Super Sport. I love both the boat and the motors, but the Detroits have always been loud at the exhaust end of things. As I grow older, this noise is starting to bother me, particularly at times when I have to shout to be heard on the flying bridge at cruise speed. Muffler companies tell me that modern
Question: I have a 1994 Mainship 31 with a pair of 315-hp Yanmar diesels with 2,000 hours on them. While running at full throttle (about 33 knots) for five minutes, the starboard engine temperature creeps up enough to set off an alarm. If I ease ‘er back to half-throttle, the temperature returns to normal after a couple of minutes. The starboard engine has always run a bit warmer
Question: While performing routine maintenance on my Caterpillar C7, I was surprised to find a substance about the size of a quarter at the top of my Racor—it looked like algae. There was no water in the bowl, and the engine-mounted filter was found to be clean. My Cat runs fine now and I would like to keep it that way. I am getting a lot of suggestions from friends as to what
Q. I have a 2003 Sea Ray Sundancer 420 and am moving from the New York City area to Florida soon. Do I need to do anything different in Florida in terms of boat maintenance? I am especially concerned about the warmer waters down there and the algae growth in fuel tanks I've heard so many bad things about.
North Haledon, New Jersey
Question: I’ve always wondered if there was anything special I should do when getting my boat ready for launch in the spring. My mechanic says no, just start her up, but I wonder.
Professor Diesel: The best advice I can give anyone is to start with the engine’s operator’s manual.